heat pump water heaters: a key energy technology for ...€¦ · heat pump water heaters: a key...
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FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
AResearchInstituteoftheUniversityofCentralFlorida
HeatPumpWaterHeaters:AKeyEnergyTechnologyforCalifornia
PassiveHouseCaliforniaApril2018
DannyS.Parker
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HeatPumpWaterHeaters(HPWH):WhatAreThey?HowDoTheyWork?
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FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
WhatYou’lllearn• Whatareheatpumpwaterheaters?• Howwelldotheyworkinthelaboratory?• Howwelldotheyworkinthefield?
– Whatdescribesbestunits?– Whataresomenon-waterheatingissues/advantages?
• Howdotheycomparewithanaturalgaswaterheater?• WhataretheimpactsonGreenhouseGases?• Whatareimpactsoncost?• Whatarenewtechnologies?
– Improvedcompressors&UEF– PVassistedHPWH
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HotWaterSystems(HWS)LaboratoryFSEC:Cocoa,Florida
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FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
FloridaSolarEnergyCenter– HotWaterSystemsLaboratory
EvaluatedMostPopularHotWaterSystems
2012EvaluatedHybrids
2014MoreHPWH’s/Hybrids
PVHPWH2016- Present
Plumber’snightmare!
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
Averaged1-YearPerformanceofWaterHeatersand1stGen.HPWHinLaboratory(Cocoa,FL)
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0.85
0.56
0.71
2.27
0.00 1.00 2.00 3.00
Dailyefficiencies (COP)
HeatPumpWH
NatGasTankless
NatGas40Gal.
50Gal.Electric
[2.35]
[0.83]
[0.91]
[0.59]
AnnualPerformance EnergyFactororUEF
Typicaloperatingefficienciesforstandardwaterheaters
ModernHPWH
FirstGenerationNos.NowUEF(likeCOP)of3.7orgreater
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
50Gal.HeatPumpWaterHeaterEfficiency
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0
0.5
1
1.5
2
2.5
3
3.5
4
40 50 60 70 80 90 100
COP
AverageDailyHWSLabInteriorTemperature(F)
WhereHPWHlocatedmatters!
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
SimulatedPerformanceofHPWHinU.S.
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WhereHPWHlocatedmatters!
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
WhatCanwelearnfromthefield?60measuredFLhomes;red=hotwater
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FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HeatPumpWaterHeaters• Dependablesavingsvs.electricresistancewater
heaters,in10homeschangedout• 80gal.models:4+personhouseholds• 68%overallsavings(5.3kWh/day)• 80gal:74%savings(7.6kWh/day)
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
NortheastHPWHStudy(MassachusettsandRhodeIsland)
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HPWHCapacity(gal) RatedEFAvg.COP %SavingsGeneralElectric50 2.35 1.82/1.61 44-55%AOSmith 60/80 2.33 2.12 58%StiebelEltron 80 2.51 2.32 61%
GEUnits=10,Stiebel Eltron =2,AOSmith=2
CostEffectiveness;simplepayback5.7yrs(avg.)- Rangeof3.2- 10.5yrs@$0.17/kWhOnlyfourHPWHleftatdefaultsetting120F(others122– 140F)
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HowDoesthisComparetoPG&E?• GasWaterHeatingmajorpartofPG&EGHGemissions• WaterheatingisBIG:90%ofPGEcustomers=gaswaterheat
• Gasusefrom2009RASSsurvey195therms or3,169kWhifelectric• Ourspreadsheetestimates203therms/2885kWhforSanJose
• 4.6millionrescustomers=4.72millionTonsCO2 peryear!• Whatareoverallcost &Carbon Impacts?
0
500
1000
1500
2000
2500
Nat.GasTank NatGas:Tankless ElecResistance HPWH PV_HPWH
AnnualCarbonImpact&$CostforWaterHeating
lbsCO2/yr $Dollars/yr
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
LessonslearnedfromMulti-FamilyHousingInstallations
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ServiceDoorcommonexteriorhallway
TransferGrillsfacingkitchenandlaundry
HPWHinconfinedsmallvolumecloset(<100ft3)
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HPWHSurveyResponseFiveMulti-FamilyComplexes
• 720HPWHUnitsinstalledinMulti-familyhomesthroughoutFlorida
• Generallyhi-acceptance• IsolatedcomplaintsFannoise• Somecomplaintsof
insufficienthotwater• FewaskhigherT’stat set
+5deg(125⁰F)
• OnecasereportedhavingturnspaceheatONbecauseofcoldairbyHPWH
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Other:QuarterlymaintenanceforairFilter,Drainagecheck
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
LaboratoryTestingtoRe-createFieldinstallationsinconfinedspace
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00.10.20.30.40.50.60.70.80.91
40
45
50
55
60
65
70
75
80
0 3 6 9 12 15 18 21 24
Cond
ensate(P
int)
ClosetTe
mpe
rature(F)
orRH(%) RH
ClosetT
Cond.Pints
15-minutedataintervals
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HPWHConfinedinClosetPerformanceAnalysis
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Days Avg. kWh/day
Avg. COP
Avg. Inlet (F)
Avg. Outlet (F)
HPWH in conditioned lab 6 2.050 2.64 74.78 118.47
HPWH in conditioned + confined space (92.5 ft3) 7 2.342 2.30 74.21 117.49
Percent increase of electric use
14% 0.292 Volume Draw
Percent COP reduction 13% 50 gal./day
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HPWHcoolsthespacewherelocated
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Canprovidefreecoolingorslightincreasestoheatingiflocatedinside
-Likesmallroomairconditioner- Running2hrs inthemorning
Potentiallyfreecoolinginsummer
Otherwisecoolergarage/utilityroom
Somedehumidificationaswell
Recommendutilityroominstall.Why?- Extraheatinthatspace(Dryer/washer)- Isolatedoftenfromrestofhome
Importanttolocateaway fromthermostat
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
HPWHAirDucting/NoiseIssue
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Mostmanufacturerson3or4th generationOfHPWH.Muchmorequiet
ForinstanceRheem unitclaimsOnly49dBforlatestunit
Othersnowmuchmorequiet
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
AirflowConfiguration
EastFRTFBuildingMeasured
Airflow (cfm)
WestFRTFBuildingMeasured
Airflow (cfm)
BuildingPressureImpactDuringHPWHOperation
GaragetoGarage(7’) 160 160 NoneIndoortoIndoor(16’) 160 157 NeutralOutdoortoIndoor(19’) 147 148 Positive
TestedAirflowPathways
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
Site
#ofOccupants Config.
HPWHEnergyPost(kWh/day)
CoolingEnergyPre(kWh/day)
CoolingEnergyPost(kWh/day)
CoolingSavings(kWh/day)
CoolingSavings(%)
ACSEER
1 4 Interior 2.1 16.3 14.5 1.8 10.8 13.05 2 Ducted 2.7 44.7 43.0 1.7 3.8 13.09 2 Ducted 3.2 11.5 10.0 1.5 13.2 <1313 2 Interior 2.6 6.8 6.1 0.7 10.7 15.526 5 Ducted 3.5 11.5 10.1 1.4 12.3 17.050 4 Ducted 2.7 18.5 17.8 0.7 3.9 17.051 2 Ducted 1.3 15.0 14.2 0.8 5.6 16.056 3 Interior 3.1 18.9 18.7 0.2 2.7 10.0
Avg. 3 N/A 2.6 17.9 16.8 1.1 7.9Med. 2.5 N/A 2.7 15.6 14.3 1.1 8.2
SpaceCoolingEnergySavings(~1yearpreand1yearpost)
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
NewTech:PV-AssistedHPWH80%+Energysavingsvs.Electricresistance
- Nomoredailyenergyusethanarefrigerator
LargereductionstoGreenHouseGasEmissionsrelativetoelectricorgaswaterheaters
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
FSEC’sPV-HPWH:Prototype• UseCurrentGenerationHPWH 80%+
energysavings• Dedicated620WPVµ-Inverters• Mixing/Anti-scaldvalve:set@125⁰C• SmartControls&programmedforadded
thermalstorage– -Normalthermostatset:125F
-Whensolaravailability=High,Auto-setthermostatto160⁰F
-OverallCOP=5.4(Florida)• Competitive;partscost($2000)retail• Conventionalsolarwaterheatersoften
>$7000- $10,000installed
310WPV+
310WPV
300-wattMicroinverters
60galHPWH
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
PV-HPWHPerformanceExample
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
PV-DrivenHPWHvsStandardElectric50gallonWaterHeater
Average=7.18kWh/dayHotWater@125⁰F =54.4gpd
Average=1.23kWh/dayHotwater@125⁰F=57gpd
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
AdvantagesofPV-HPWH• Superiorperformancetosolarthermal• Nonet-meteringagreement• Muchlowercostthan(perhapshalfsolarthermal)• Simple&fastinstall:Noplumbing,light-weightmodules• Betterwinterperformance:nofreezeprotection
– PVoutputhigherinwinter,nopipinglosses• Solidstate=Morereliable/longerlife
– lowermaintenancethansolarthermal• Stores2.3kWhthermal/dayaboveset@nocost• Produceshotwatereveninapoweroutage• Betterfutureperformanceavailable
– HPWHCOPsnow3 – 3.5vs.prototypecompressor(2.2)– PVmoduleefficienciesincreasing=smallermodulefootprint
• Seasonaltilttrackingpossiblegivensmallsize
• Disadvantage:notyetmanufactured
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
SpreadsheettoEstimateAllThisforYouOnlyafewinputs:fairlysophisticatedestimationofwaterdemand;sizeofhouseholdandagesYes,researchshowsteenagersuse3xasmuchhotwater
FLORIDASOLARENERGYCENTER— AResearchInstituteoftheUniversityofCentralFlorida
ALittleSummary• HPWHinstall:Building
locationimportant– Garagemayreducewinter
efficiency– Locateawayfromthermostat
• Interiorlocationcanprovidehelpfulsummercooling
• Whenductingair,knowwhereairiscomingfrom
• Compressoroperationlimitedw/ambienttempsbelow40⁰F.NotbiglimitationinCA
• HPWHisidealformildU.S.climates
• LargeGHGreductions• HPWHbesttechnologyfor
waterheatinginanallelectrichome
• FuturePV-HPWHtechnologypromiseslesswaterheatingenergythanarefrigerator
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